In recent years, a camera is mounted to a smartphone, a mobile phone device, or a tablet terminal. An image quality and a usability of the camera are improved, whereby a general user captures a number of images. In addition, a variety of net services handling the images is spreading. In this way, an amount of the images handled by a user is explosively increased.
Then, in order to browse a number of images effectively, a technology to classify and display the images along a time axis of year, month, and day.    [Patent Document 1] Japanese Patent Application Laid-open No. 2007-179351